Earth/neutral Bars For Disribution Board?

[mcinnes01]

Hi,

I am doing an automation system using a number of contactors and 2 large steel enclosures which I have mount din rails to the back plate.

I am trying to find out the best way of commoning the earth and neutrals.

All I have found so far are the following 383-1548 and 413-2274 from rs components. (sorry can't post urls yet)

Neither of which seem particularly readily available so I am starting to wonder if this isn't the typical way of doing this.

The enclosures are large 1000x800x300 mm.

Each has 8 din rails running horizontal and both have a proper steel back plate. (enclosures are fully earthed)

Any suggestions would be most welcomed.

Andy

Sorry correct 6 din rails per enclosure.

Sorry 6 rails per enclosure.

 

[M107]

Use the din mount units & jumpers from the forum sponsor wago box

https://www.wagobox.com/shop/topjob-din-rail-mounted-terminals/2004-series?p=2

 

[Sidewinder]

What's the matter with these for the Earths?

http://uk.rs-online.com/web/p/earth-blocks/5280217A/

In an appropriate size obviously.

Why are you linking the N between enclosures?

Why not use a single enclosure?

 

[mcinnes01]

Hi,

I am not joining N between enclosures. Each enclosure is located at opposite ends of the building fed by swa. RCDs break each box down in to 2 circuits which are further broken down by breakers to form banks of contactors.

This may seem a silly question but as I may have around 70 cables coming in to each enclosure, each needing earthing, its neutral connecting up appropriates and it live to go to the supply from the contactor. How do the 2 way din terminals benefit, do you just use them to provide earth and neutral next to each contactor so you its neater and then link the terminals together?

many thanks

andy

 

[SBS Dave]

Hi mcinnes01,

If I understand you correctly, you are trying to duplicate the earth / neutral bar arrangement you would find in a Standard Consumer Unit.

The difference being, course, that your "CU" is 1000mm wide.

If that is the case, please tell me how many earth terminals and neutral terminals you need per bar and whether they have to be continuous terminal bars, or if they can be bars joined together with copper links, as per a 17th Edition Board. I may be able to come up with a novel solution to your problem.

I assume the final enclosure will be subject to BSEN60439, as a PTTA.

SBS Dave

PS, Just realised you are in Manchester.

There is a Company in Bredbury, Stockport, that can satisfy your needs, using DIN rail mounted terminal strips, up to 1000mm in length.

It is

MGB Electrical (Incorporating A.Davies )

Tel 0161 880 0200

e-mail  [email protected]

 

[Sidewinder]

You can common up the terminals, the WPE type automatically common through the teeth that grip the DIN rail.

The "live" terminals you common with a jumper bar.

Another quick Q, why are you using RCD's this sounds industrial/commercial, they are not always needed, and, can be a nuisance.

You are using contactors, what are these controlling?

It sounds like you may be straying away from BS7671 and into control systems, so, that is a whole different set of standards etc.

We can help, but we need to understand more.

For example, if it is a control system you are building, this would come under BS EN 60204-1.

You cannot use "mains" supplies for control devices such as contactor coils, push buttons etc. they must be transformer fed with circuit protection either side.

Personally, when I build panels like this I use DIN rail terminals such as the Weidmuller SAK & WPE types with jumpers etc. as appropriate.

Remember though if you "NEED" your earthing to be independent per circuit, you can't use a WPE type of terminal you would need to use an insulated terminal rather than an earthed type.

 

[mcinnes01]

Hi,

Thanks for all the replies.

The contactors will be controlled by an isolated 24v control system yes. This is mainly controlling lighting and some domestic appliances, although somewhat industrial sounding it is for a residential automation system.

@SBS Dave Yes I am basically replicating a standard CU but on a slightly larger scale.

@Sidewinder I am using RCDs as this is for residential project and essentially is just a large CU albeit with a lot of contactors.

To add a little more detail, to make the system more modular I have all my MCBs and RCDs in 2 standard WYLEX CUs. This then provides the feed for the separate circuits that will be housed in the steel enclosure. So each steel enclosure has a CU above it and each CU has an adaptable box providing a feed from an SWA. The meter tails go in to an isolator switch and then come out in to an adaptable box where they are split in to the 2 swa cables which feed the 2 CUs.

The Earth will be common as in a normal CU in the steel enclosures.

Each enclosure will house up to about 60 contactors, but one will be a little less, maybe as few as 36 contactors.

The low power switching is fed by a din mounted 24v power supply in each enclosure and low voltage control board which will be fully isolated will be used to switch the coils of the contactors and is controlled by wifi. This means the low voltage swtich gear will be self contained and isolated within the steel enclosures with no need for low voltage cables or controls to come out of the enclosures.

@CanoeBoy The link you provided is quite interesting, which of the products would you suggest for these enclosures based on the potential number of contactors? I plan on arranging the contactors logically and arrange them back to back, i.e. so that the 240v side of 2 rows of the contactors will be together and then 2 rows of the 24v will be together. All mains it to be kept to the right side of the enclosures, with low voltage going to the left.

Do you have any suggestions on cable management? As you can imagine there is a fair old bundle of cables coming in to these enclosures and I want to ensure they are kept as organised and secure as possible.

Many thanks,

Andy

 

[mcinnes01]

Hi,

I am just about to start getting an order together for my the guts of my distribution boards and wondered if you can point me in the right direction.

What I am doing is very similar to how you would wire a panel and from reading around and the advice above it would seem that the standard is to use din terminals.

The dilemma I have is which to get...

The seems to be a couple of options, the bus bar method as CanoeBoy suggested or standard din terminals and the terminal bars to connect them together.

I would ideally like a fairly compact solution in order to utilise the space in my enclosures better.

I have also purchased some cable management trunking to keep things nice and tidy.

I guess what I am looking for is some links to specific products that would meet my needs. This is just controlling standard domestic appliances so the ratings are what you would typically expect.

In total if I try to work on the principle that I have 100 connections so I need terminals to connect:

60 Neutrals and 60 Earths in one enclosure

40 Neutrals and 40 Earths in the other enclosure.

I am a little unsure as to exactly what I will need as there seem to be a few various parts to the din terminal solutions with end plates, tensions, bus bars, etc.

Also as I have said I am going to need enough for 100 connections, and having not used these before I am a little unsure what to expect pricewise, but I typically use RS components and there seems a fairly broad range of prices from as little as 37p per terminal up to a few quid?

Any cost effective suggestions, recommend supplies and exactly what bits I will need to get all together would really help me out

Thanks again,

Andy

 

[steptoe]

is this a DIY install?

it sure sounds like it from my chair,,,,,,,,

 

[mcinnes01]

Its DIY in terms of the automation system, but everything is being done, signed and tested by a qualified spark.

I am an electronic engineer and am designing the control boards, so I am guiding my spark as to how I want my distribution boards configuring and what I want to use.

As you will appreciate I can do electronics, but don't pretend to know or perform mains electrical standards or connections.

That's why I am looking for tips on which are the best products to use for this more industrial style install.

 

[steptoe]

OK, no worries,

I just think you would have been better getting a spark that could actually advise you on what you needed TBH.

it often ends in tears when the householder provides kit , the spark doesnt know what he is doing and then blames the stuff supplied,

if your spark doesnt know what to fit, chances are he wont understand how to connect it either,,,,,,,,,

 

[mcinnes01]

Its a fair point and I am confident he will manage, once we agree on a structure it should be relatively straight forward as the only complexity is the number of connections as everything is the same and just needs repeating over and over.

The reason I ask for product advice is because there are so many ways to do this and there will be people on here that wire banks of contactors every day. My spark could easily wire this up now, as could I, but what I am looking for is best practice/ recommended products. As you know there are many ways to do something and some will be right, others will be wrong and some will be better than others. I am looking for the "better than others" option .

 

[steptoe]

Its a fair point and I am confident he will manage, once we agree on a structure it should be relatively straight forward as the only complexity is the number of connections as everything is the same and just needs repeating over and over.

The reason I ask for product advice is because there are so many ways to do this and there will be people on here that wire banks of contactors every day. My spark could easily wire this up now, as could I, but what I am looking for is best practice/ recommended products. As you know there are many ways to do something and some will be right, others will be wrong and some will be better than others. I am looking for the "better than others" option .

fair enough,

at least you are exploring your options,

 

[SBS Dave]

Hi mcinnes01,

Maybe I am misunderstanding your problem, but if all you need is a method of connecting up to 60 neutrals, or 60 earths, all in a row, then the Company I mentioned would have a solution.

They sell 1000m lengths of brass terminal strip, giving  165 x 6mm terminals. They also sell either DIN rail supports or Base mounted brackets, for fixing directly to the enclosure. You just cut it to the desired length and fit it to an existing DIN rail or to the metal box directly.

SBS Dave